Lasers may emit light through a process called stimulated emission. Laser light can be temporally and spatially coherent, where the light can either be emitted in a narrow, low-divergence beam, or can be converted into one with the help of optical components such as lenses. For coherent light, the source of the light may produce light waves that are in step and have the same frequencies and identical phase. Lasers may be employed over a huge range of applications including basic scientific research, test and measurement, industrial processing, microelectronics, biomedicine, environmental science, avionics, entertainment and telecommunications.